Process for the treatment of liquids by oligodynamy and particularly the treatment of sullage waters

Abstract

The invention concerns a method of treating liquids by means of oligodynamy, particularly of sullage waters. The waters are passed between metal electrodes supplied with electric current before being allowed to settle. The waters which have been subjected to the oligodynamic treatment are then submitted to at least one positive degassing operation and/or a part at least of the flocculate being formed is recovered and said flocculate is re-introduced into the water which has just flowed between the metallic electrodes. The flocculate resulting from the treated waters is then separated.

I claim: 
     
       1. A method for purifying liquids by means of oligodynamy, consisting essentially of: regularly passing the totality of the liquids between electrically supplied metal electrodes, whereby the liquids are treated and metal ions are homogeneously dissipated in the treated liquids to provide formation of flocculates;   subjecting the treated liquid to a physical treatment which causes a substantial quantity of gas bubbles to separate from the flocculates just being formed in the liquid;   removing the separated air bubbles; and   separating the flocculate and evacuating purified liquids.   
     
     
       2. A method in accordance with claim 1 further including the step of recovering at least a part of the flocculate and reintroducing the recovered flocculate into the treated liquids. 
     
     
       3. A method in accordance with claim 2 wherein the recovered flocculate is reintroduced into the treated liquids prior to the completion of said step of separating gas bubbles. 
     
     
       4. A method according to one of claims 1 or 3, wherein said step of separating and removing gas bubbles is made in a degassing vessel comprising a succession of tanks or basins, said liquids being then carried into a decantation tank with multiple compartments and increasing volumes comprising exhaust means for decanted flocculates, exhaust means for purified liquids and exhaust means for gases. 
     
     
       5. A method according to one of claims 1 or 3, wherein said step of separating and removing gas bubbles is made in a degassing vessel comprising a chamber in which the liquids are driven in a gyratory movement, said liquids being then carried into the decantation tank with multiple compartments and increasing volumes comprising exhaust means for decanted flocculates, exhaust means for purified liquids and exhaust means for gases. 
     
     
       6. A method according to claim 5, wherein the degassing vessel is connected to an air-tight decantation chamber, the metal electrodes being connected to the degassing vessel via an air-tight duct, and wherein degassing valves are provided at least in relation with the degassing chamber. 
     
     
       7. A method for purifying liquids by means of oligodynamy, consisting essentially of the steps of: regularly passing the totality of the liquids between electrically supplied metal electrodes, whereby the liquids are treated and metal ions are homogeneously dissipated in the treated liquids to provide formation of flocculate;   separating the flocculate and reintroducing at least a part thereof into the treated liquids; and   evacuating purified liquids.   
     
     
       8. A method in accordance with claim 7 further including the step, immediately after said passing step, of separating a substantial quantity of the gas bubbles in the liquid from the flocculates just being formed. 
     
     
       9. A method according to one of claims 1 or 7, further including the step of leaving the flocculate to grow for a time longer than one hour before separating it from the liquids. 
     
     
       10. A method in accordance with claim 9, wherein the flocculate is left to grow for a time of the order of one and a half hours. 
     
     
       11. A method according to one of claims 1 or 7, further including the step of adding oxygen to the liquids separated from the flocculate. 
     
     
       12. A method according to one of claims 1 or 7, wherein the oligodynamically active metal electrodes are electrically adjusted as a function, on the one hand, of the nature of the metals forming them and, on the other hand, of the liquids to be treated, whereby the metal of the electrodes reacts with the metals and metallic salts in the treated liquids. 
     
     
       13. A method according to one of claims 1 or 7, further including the step of adding to the oligodynamically treated liquids chemical ingredients for promoting growth fo the flocculate and acting on turbidity or hardness of the liquids. 
     
     
       14. A method according to one of claims 1 or 7, wherein the step of passing the liquids between oligodynamically active metal electrodes is made through an odd number of electrodes. 
     
     
       15. A method according to one of claims 1 or 7, wherein the step of passing the liquids between oligodynamically active metal electrodes is made through at least two sets of electrodes. 
     
     
       16. A method according to one of claims 1 or 7, wherein the step of passing the liquids between oligodynamically active metal electrodes is made by using electrodes of iron.